1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor device, and more particularly, to a method of forming a sidewall oxide films for protecting a gate electrode at the sidewall of the gate electrode in a flash memory cell.
2. Background of the Related Art
In general, in implementing the flash memory devices, after the gate electrode is formed, a dry oxidization process using O2 is implemented for the gate sidewall in order to compensate for etch damage obtained when the floating gate is isolated and gate is etched. At this time, it is advantageous to thickly form the sidewall oxide films formed by sidewall oxidization from the viewpoint of sidewall reinforcement and compensation of etch damage. In order to form a thick sidewall oxide film, however, an oxidization process is performed for a long period of time. Thereby, a smiling phenomenon occurs that the thickness around the sidewalls of first and second oxide films and a tunnel oxide film among the dielectric film of a first oxide film/a nitride film/a second oxide film (oxide/nitride/oxide, ONO) structure that has been widely used as the dielectric film in the flash devices is increased. This causes to degrade characteristics of the device.
Accordingly, the present invention is contrived to substantially obviate one or more problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a method of manufacturing a semiconductor device capable of prohibiting a smiling phenomenon by implementing dry oxidization using an adequate mixed ratio of O2 and TCA (tri-chloro-ethane, C2H2Cl3) in a sidewall oxidization mode.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a method of manufacturing a flash memory device according to the present invention is characterized in that it comprises the steps of providing a semiconductor substrate in which a gate electrode including a tunnel oxide film, a floating gate, a dielectric film and a control gate is formed, and implementing a dry oxidization process using a mixed gas of O2 and C2H2Cl3 to form sidewall oxide films at the sidewalls of a gate electrode in order to compensate for damage due to an etch process for forming the gate electrode and reinforce isolation of the floating gate.
In another aspect of the present invention, it is to be understood that both the foregoing general description and following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.